Back Surface Electrode Roughness for Semiconductor Adhesion

Solution Overview

Problem

The adhesion between the back surface electrode and the sealing member in semiconductor devices, particularly those with power transistors, is poorer than the adhesion between silicon and the sealing member, which affects the reliability of the semiconductor device.

Innovation Solution

Forming an uneven shape on the front surface of the back surface electrode on the semiconductor chip to enhance the anchor effect and improve adhesion with the sealing member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a vertical structure power transistor is adopted to improve integration degree and achieve miniaturization, then the degree of integration is improved, but the adhesion between the back surface electrode and the sealing member deteriorates

Engineering Contradiction:

Improvedegree of integrationVSAvoidadhesion between back surface electrode and sealing member

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies surface roughening to the back surface electrode, transforming it from a flat surface to a curved/uneven surface structure. This curvature increase creates mechanical interlocking with the sealing member, resolving the adhesion problem caused by the vertical power transistor structure while maintaining miniaturization benefits.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the surface parameters of the back surface electrode by controlling the roughness within a specific range (Ra: 0.5μm to 5μm). This parameter modification improves adhesion strength without affecting the electrical performance or the miniaturization achieved through the vertical structure.

Inventive Principle:

Principle #35Parameter changes

2Power

If the back surface electrode is formed on the semiconductor chip for vertical structure power transistors, then the current conduction is improved, but the adhesion between the electrode and sealing member deteriorates compared to silicon adhesion

Engineering Contradiction:

Improvecurrent conductionVSAvoidadhesion between back surface electrode and sealing member

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies surface roughening to the back surface electrode, transforming it from a flat surface to a curved/uneven surface structure. This curvature increase creates mechanical interlocking with the sealing member, resolving the adhesion problem caused by the vertical power transistor structure while maintaining miniaturization benefits.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the surface parameters of the back surface electrode by controlling the roughness within a specific range (Ra: 0.5μm to 5μm). This parameter modification improves adhesion strength without affecting the electrical performance or the miniaturization achieved through the vertical structure.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively improves the adhesion between the back surface electrode and the sealing member, enhancing the reliability and reducing the risk of peeling, thereby contributing to a more reliable semiconductor device.

Implementation Method 1

an uneven shape is formed on a front surface of a back surface electrode formed on a back surface of the semiconductor chip

Methodology Applied

Scientific EffectMechanical interlocking:

Data Source

PatentUS10777475B2Semiconductor chip, semiconductor device, and electronic device

Publication Date: 2020.09.15 RENESAS ELECTRONICS CORP

AI summary

In order to improve reliability of a semiconductor device, in a semiconductor chip according to one embodiment, an uneven shape is formed on an exposed surface of a back surface electrode formed on a back surface of the semiconductor chip.